The putpclcdelta function set the DWARF line number PC to
s->value + pcline->pc, which is correct, but the code then set
the local variable pc to epc, which can be a different value.
This caused the next delta in the DWARF table to be wrong.

Fixes #8098.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/104950045